In the operation of internal combustion engines, use is conventionally made of air intake systems which provide ram or resonance pipe charging or a combination of these two charging types. In the case of a supercharged internal combustion engine, the compression of the combustion air which is sucked in results in an increase in the air temperature. Further charging is avoided and a charge-air cooler for cooling the charge air is therefore positioned downstream of a compressor. This is intended to minimize the risk of a knocking engine. A further reduction in the charge-air temperature by means of a larger charge-air cooler is generally not possible for structural reasons. Accordingly, to increase the efficiency of the charge-air cooler, expansion devices are provided downstream thereof in order to further reduce a combustion air temperature. DE 100 02 482 A1 discloses for example a device for charge-air cooling of said type, in which the combustion air which is at an increased charge pressure is expanded at a back-pressure valve. Here, the back-pressure valve is positioned between the charge-air cooler and the air intake system of the internal combustion engine.
DE 36 27 312 A1 likewise discloses an expansion control device for lowering the charge-air temperature, by means of which expansion control device an adiabatic partial expansion of the supercharged air is obtained. Here, the expansion control device has a nozzle-like line section which is designed in the manner of a laval nozzle, with the nozzle-like line section being arranged in the intake line upstream of the air intake system. The measures known from the prior art for cooling the charge air downstream of the outlet out of the charge-air cooler necessitate the arrangement of an expansion device in the intake line, and thereby entail additional structural expenditure in the engine bay of the vehicle.